• Title/Summary/Keyword: sulfate environment

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Characterization of Size distribution of Anion Species in Atmospheric Aerosols (대기에어로졸중 음이온성분에 대한 입경분포의 변화특성)

  • 최금찬;박정호;임경택
    • Journal of Korean Society for Atmospheric Environment
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    • v.10 no.2
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    • pp.124-129
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    • 1994
  • Aerosol size distribution was determined using Anderson sampler for the anions( sulfate nitrate and chloride ) and TSP. Ionic species concentration and size distribution have been investigated in the daytime and nightime individually. Size classified samples were extracted with distilled water and analyzed for C $l^{[-10]}$ , N $O_3$$^{[-10]}$ and S $O_4$$^{2-}$, by ion chromatography. The size distribution of these ions and TSP was analyzed to investigate the seasonal and diurnal variation of concentrations as follows: (1)Size distribution of TSP showed bi- modal type in the daytime, but indicated tri-mode distribution in the nightime without any seasonal variation. (2)Sulfate concentrations were higher in fine- mode both in the daytime and nightime but fraction of sulfate was higher in coarse-mode during the Yellow Sand Period. (3)Nitrate and Chloride ions are dominant in fine-mode in winter while dominant in coarse-mode in the summer.

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Temperature Effects on the Persulfate Oxidation of Low Volatile Organic Compounds in Fine Soils (과황산나트륨 산화에 의한 토양내 저휘발성 유기오염물 제거 시 온도의 영향 평가)

  • Jeong, Kwon;Kim, Do-Gun;Han, Dai-Sung;Ko, Seok-Oh
    • Journal of Soil and Groundwater Environment
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    • v.17 no.2
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    • pp.7-14
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    • 2012
  • Batch tests were carried out to evaluate the thermal treatment of low volatile organic compounds in low-permeability soil. The chemical oxidation by sodium persulfate catalyzed by heat and Fe (II) was evaluated. Enhanced persulfate oxidation of n-decane (C-10), n-dodecane (C-12), n-tetradecane (C-14), n-hexadecane (C-16), and phenanthrene was observed with thermal catalyst, indicating increased sulfate radical production. Slight enhancement of the pollutants oxidation was observed when initial sodium persulfate concentration increased from 5 to 50 g/L. However, the removal efficiency greatly decreased as soil/water ratio increased. It indicates that mass transfer of the pollutants as well as the contact between the pollutants and sulfate radical were inhibited in the presence of solids. In addition, more pollutants can be adsorbed on soil particles and soil oxidant demand increased when soil/water ratio becomes higher. The oxidation of the pollutants was significantly improved when catalyzed by Fe(II). The sodium persulfate consumption increased at the same time because the residual Fe(II) acts as the sulfate radical scavenger.

Measurement Study at Kosan, Cheju Island during March-April, 1994: (I) Transport of Ambient Aerosol (고산에서의 1994년 3월 - 4월 측정연구: (I) 입자상 오염물질의 이동)

  • 김용표;박세옥;김진영;심상규;문길주;이호근;장광미;박경윤;강창희
    • Journal of Korean Society for Atmospheric Environment
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    • v.12 no.1
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    • pp.79-90
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    • 1996
  • Total suspended particles were measured at Kosan, Cheju Island, Korea during the period of March 11 .sim. April 19, 1994. Concentrations of non-sea salt(nss) ions were higher than those measured at clean marine areas in Japan and other background marine areas in the world. Especially, nss sulfate concentration is compatable to thoes measured at Seoul. It is suggested that most nss sulfate concentration is originated from anthropogenic sources. Nss sulfate concentration shows strong correlation with ammonium and nss potassium concentrations while shows no a pparent correlation with nitrate and nss calcium concentrations. Nss calcium concentrations shows strong correlation with nss potassium and mss magnesium concentrations. It is deduced that nss potassium has two origins, one anthropogenic, the other crustal. Backward trajectory analysis results show the trajectories of air parcel during the measurement period were mostly originated from China. It is shown that cases of high nss sulfate with high nss calcium can occur when an air parcel originated from arid and semi-arid regions of morthwestern China or Mongolia passes through northeastern China.

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Evaluation of Affecting Factors on the Ferrous Catalyzed Sodium Persulfate Oxidation for the Destruction of Organic Pollutant (과황산나트륨을 이용한 유기 오염물 산화와 영향인자 평가)

  • Yun, Yeobog;Park, Haimi;Ko, Sunghwan;Ko, Seokoh
    • Journal of Korean Society on Water Environment
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    • v.25 no.1
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    • pp.151-158
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    • 2009
  • The objective of this study was to determine on optimum ratio of oxidant and catalyst and to evaluate affecting factors such as anions and cations on persulfate oxidation of organic pollutant. Fe(II) activated the persulfate anion to produce a sulfate free radicals and thus effectively used to degrade the target organic pollutant in aqueous system. The chloride ions reacted with sulfate radical produced the $Cl^{\cdot}$ atom and had positive effects on the oxidation of organic pollutant at the initial stage. However, it was observed that chloride ions had the scavenging effects on the rate of oxidation of organic pollutant. Cations and some heavy metals were partly able to activate the persulfate anion to generate a sulfate free radical. However, high levels of cations inhibited the oxidation of organic pollutant.

Effects of Nitrogen and Potassium Sources on Growth and Yield of Strawberry 'Seolhyang' and 'Maehyang' in Fertigation Culture (딸기 '설향' 및 '매향'의 관비재배 시 질소 및 칼리의 공급원이 생육 및 수량에 미치는 영향)

  • Kim, Seung-Yu;Jang, Yoon-Ah;Moon, Ji-Hye;Lee, Jun-Gu;Lee, Sang-Gyu;Cha, Seon-Hwa
    • Journal of Bio-Environment Control
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    • v.18 no.4
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    • pp.436-441
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    • 2009
  • The experiment was conducted to investigate the effect of nitrogen and potassium sources on growth and yield of strawberry 'Seolhyang' and 'Maehyang' in fertigation culture. The plant fresh and dry weight were higher in urea + potassium sulfate and ammonium sulfate + potassium sulfate as nitrogen and potassium sources than others in both varieties. But there were no significant difference among nitrogen and potassium sources in other growth characteristics, such as plant height, no. of leaf, crown diameter etc. Also, the marketable yield of fruit were higher in urea + potassium sulfate and ammonium sulfate + potassium sulfate in 'Seolhyang' than other treatments. 'Maehyang' was better in both treatments but there was no significant difference. The fruit qualities, such as total soluble solid, hardness, acidity, vitamin C content were not significant difference among the treatments. The acidity of soil was tended to decrease but EC was tended to increase highly in ammonium sulfate treatments as a nitrogen source. As above results, the urea and potassium sulfate were recommended as nitrogen and potassium sources for the fertigation culture of strawberry 'Seolhyang' and 'Maehyang'.

Recovery of Sodium Sulfate from Farm Dyainage Salt and Using It in Directive Dyeing of Cotton

  • Jiyoon Jung;Kwon, Ghi-Young
    • The International Journal of Costume Culture
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    • v.4 no.2
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    • pp.86-93
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    • 2001
  • Agricultural drainage salt generated during irrigation of crops in San Joaquin Valley, California exceeds 600,000 tons annually and cumulates in the field in a rapid rate. As a result, the waste is taking out more farmlands for salt storage and disposal, imposing serious concerns to environment and local agricultural industry. in searching for a potential solution to reduce or eliminate the waste, this research explored feasibility of producing a value-added product, sodium sulfate, from the waste and utilizing the product in textile dyeing. The result indicated that sodium sulfate could be produced the salt and could be purified by a recrystalization method in a temperature range within the highest and lowest daily temperatures in summer in the valley. Re recovered sodium sulfate samples, with purifies ranging from 67% to 99.91, were compard with commercially available sodium sulfate in directive dyeing of cotton fabrics. Direct Yellow 27 and direct Blue 1 had similar exhaustions among Na₂So₄Ⅰ, Na₂So₄Ⅱ, Na₂So₄Ⅲ and V which had similar ratios of sodium sulfate and sodium chloride in recovered salts. Na₂So₄Ⅳ had high exhaustion despite low ratios of sodium sulfate and sodium chloride. In direct Red 80, exhaustion depends more on the ratios of sodium sulfate and sodium chloride than sodium chloride. Na₂SO₄Ⅳ and Na₂SO₄V with high ratios of sodium chloride had more exhaustion than Na₂So₄and Na₂So₄Ⅲ with low ratios of sodium chloride. Generally, directive dyeing using recovered salts from farm drainage has similar or more excellent exhaustion than directive dyeing using commercial sodium sulfate.

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Preparation of Calcium Sulfate α-Hemihydrate from FGD Gypum in the Autoclave (가압반응기를 이용한 배연탈황석고로부터 α형 반수석고의 생성)

  • Park, Seung-Soo;Kim, Ki-Hyoung;An, Hi-Soo;Park, Kwang-Kyu
    • Applied Chemistry for Engineering
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    • v.17 no.6
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    • pp.619-624
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    • 2006
  • This study was performed to investigate the formation process of calcium sulfate ${\alpha}$-hemihydrate from FGD gypsum produced at thermal power plant burning bituminous coal. The experimental results showed that calcium sulfate $\alpha$-hemihydrate with a large aspect ratio was produced in the temperature range of $120^{\circ}C$ and $140^{\circ}C$ in the absence of additives through dissolution-recrystallization mechanism. It was also observed that addition of Na-succinate as a catalyst changed crystal shape from acicular to prismatic, resulting in decreased water/powder ratio down to 33%. Optimum concentration of Na-succinate was 20mM. It was confirmed that the optimum moulding pressure and moisture content of moulded body from FGD gypsum were $30kg_f/cm^2$ and between 10% and 15% respectively, which prevent moulded body from collapsing and maximize the capillary effect by given pore volume while autoclaving.

Neuro-fuzzy based prediction of the durability of self-consolidating concrete to various sodium sulfate exposure regimes

  • Bassuoni, M.T.;Nehdi, M.L.
    • Computers and Concrete
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    • v.5 no.6
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    • pp.573-597
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    • 2008
  • Among artificial intelligence-based computational techniques, adaptive neuro-fuzzy inference systems (ANFIS) are particularly suitable for modelling complex systems with known input-output data sets. Such systems can be efficient in modelling non-linear, complex and ambiguous behaviour of cement-based materials undergoing single, dual or multiple damage factors of different forms (chemical, physical and structural). Due to the well-known complexity of sulfate attack on cement-based materials, the current work investigates the use of ANFIS to model the behaviour of a wide range of self-consolidating concrete (SCC) mixture designs under various high-concentration sodium sulfate exposure regimes including full immersion, wetting-drying, partial immersion, freezing-thawing, and cyclic cold-hot conditions with or without sustained flexural loading. Three ANFIS models have been developed to predict the expansion, reduction in elastic dynamic modulus, and starting time of failure of the tested SCC specimens under the various high-concentration sodium sulfate exposure regimes. A fuzzy inference system was also developed to predict the level of aggression of environmental conditions associated with very severe sodium sulfate attack based on temperature, relative humidity and degree of wetting-drying. The results show that predictions of the ANFIS and fuzzy inference systems were rational and accurate, with errors not exceeding 5%. Sensitivity analyses showed that the trends of results given by the models had good agreement with actual experimental results and with thermal, mineralogical and micro-analytical studies.

Acidic Properties and Catalytic Activity of Titanium Sulfate Supported on TiO2

  • Sohn, Jong-Rack;Lee, Si-Hoon;Cheon, Park-Won;Kim, Hea-Won
    • Bulletin of the Korean Chemical Society
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    • v.25 no.5
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    • pp.657-664
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    • 2004
  • Titanium sulfate supported on $TiO_2$was prepared by impregnation of powdered $TiO_2$with an aqueous solution of titanium sulfate followed by calcining in air at high temperature. For Ti$(SO_4)_2/TiO_2$ samples calcined at 300 $^{\circ}C$, no diffraction lines of titanium sulfate are observed at $Ti(SO_4)_2$loading up to 30 wt%, indicating good dispersion of $Ti(SO_4)_2$ on the surface of $TiO_2$. The acidity of the catalysts increased in proportion to the titanium sulfate content up to 20 wt% of $Ti(SO_4)_2$. 20 wt% $Ti(SO_4)_2/TiO_2$ calcined at 300 $^{\circ}C$ exhibited maximum catalytic activities for 2-propanol dehydration and cumene dealkylation. The catalytic activities for these reactions, were correlated with the acidity of catalysts measured by ammonia chemisorption method.

Alkali-activated GGBS and enzyme on the swelling properties of sulfate bearing soil

  • Thomas, Ansu;Tripathia, R.K.;Yadu, L.K.
    • Geomechanics and Engineering
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    • v.19 no.1
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    • pp.21-28
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    • 2019
  • Use of cement in stabilizing the sulfate-bearing clay soils forms ettringite/ thaumasite in the presence of moisture leads to excessive swelling and causes damages to structures built on them. The development and use of non-traditional stabilisers such as alkali activated ground granulated blast-furnace slag (AGGBS) and enzyme for soil stabilisation is recommended because of its lower cost and the non detrimental effects on the environment. The objective of the study is to investigate the effectiveness of AGGBS and enzyme on improving the volume change properties of sulfate bearing soil as compared to ordinary Portland cement (OPC). The soil for present study has been collected from Tilda, Chhattisgarh, India and 5000 ppm of sodium sulfate has been added. Various dosages of the selected stabilizers have been used and the effect on plasticity index, differential swell index and swelling pressure has been evaluated. XRD, SEM and EDX were also done on the untreated and treated soil for identifying the mineralogical and microstructural changes. The tests results show that the AGGBS and enzyme treated soil reduces swelling and plasticity characteristics whereas OPC treated soil shows an increase in swelling behaviour. It is observed that the swell pressure of the OPC-treated sulfate bearing soil became 1.5 times higher than that of the OPC treated non-sulfate soil.